The present invention pertains to a web expanding device for a web-processing machine or in a web-processing machine, in which a material web to be processed, e.g., a plastic film or metal foil or especially a paper web is delivered endlessly and processed in the process. The processing machine may be especially a rotary printing press, preferably for printing large circulations of newspapers.
DE 100 23 169 A1 describes a web expanding device with two arrow-shaped turning bars, which are arranged one after another behind a longitudinal cutting means in the direction of web delivery and are mounted movably in relation to one another in a machine frame. Due to the adjustment of the two arrow-shaped turning bars in relation to one another, two web strands of a web cut lengthwise can be offset in parallel to one another and expanded apart from each other as a result. The expanding device has a compact design. The two web strands are offset in parallel symmetrically in relation to the longitudinal cut, i.e., by the same amount of offset each.
The object of the present invention is to increase the flexibility of a web expanding device in terms of the possible guiding of the web.
The present invention pertains to a web expanding device, which is arranged in a web-processing machine or is intended to be arranged in a web-processing machine. It is used to create a distance between parallel web strands at right angles to a direction of web delivery or to preferably increase a distance that may already possibly be present. The web expanding device is inserted into the machine or is arranged in the machine preferably in front of a processing unit acting on the web, and in the case of a plurality of processing machines, it is preferably arranged in front of the processing unit that is the first processing unit when viewed in the direction of web delivery in order to set the position of the web strands in relation to the processing unit or the plurality of processing units at right angles to the direction of web delivery. The direction of web delivery is generally defined below as the longitudinal direction of the uncut web, and the longitudinal direction of the web strands offset in parallel is also designated by the same name.
The web expanding device comprises a frame, a cutting means for longitudinally cutting a web into a left-hand web strand and at least one additional, right-hand web strand, at least two left-hand deflecting means for the left-hand web strand and at least two right-hand deflecting means for the right-hand web strand. The deflecting means each point obliquely to the direction of web delivery. In the production, e.g., a print production, the left-hand deflecting means are wrapped around by the left-hand web strand and the right-hand deflecting means by the right-hand web strand, i.e., each of the deflecting means forms a deflection axis for the web strand with which it is associated. Each of the deflecting means may be formed especially in the manner of a turning bar. One of the deflecting means may also be formed by one rotatably mounted deflecting roller each, which is advantageous for the guiding of the web, but increases the complexity of the web expanding device.
The at least two left-hand deflecting means are arranged one after another in the direction of web delivery. They will therefore hereinafter be called the first upstream left-hand deflecting means and the second downstream left-hand deflecting means. They are preferably arranged in the path of the left-hand strand directly one after another, i.e., no additional deflecting means which would wrap around the left-hand web strand is located between them. What was said in connection with the left-hand deflecting means applies in the same manner concerning the right-hand web strand to the at least two right-hand deflecting means, which will hereinafter be called the first right-hand deflecting means and the second right-hand deflecting means. It should also be noted concerning the arrangement of the deflecting means that the first left-hand deflecting means and the first right-hand deflecting means point toward each other in a top view of the web, and the deflection axes formed by them form an angle of less than 180xc2x0 in the top view. The second left-hand deflecting means and the second right-hand deflecting means also point toward each other in the top view, and the deflection axes of these deflecting means also form an angle of less than 180xc2x0 in the top view. If the deflecting means or some of the deflecting means in the frame are mounted pivotably in the frame in order to pivot the deflecting means or some of the deflecting means for the purpose of an angular adjustment in the plane of the web or in the plane of the web strands, it is, however, also possible to conceive the case in which the deflecting means that are to point toward each other are aligned in one pivoted position, but no expansion will then be performed by the deflecting means in question.
The deflecting means are shaped and arranged in relation to one another such that the left-band web strand and the right-hand web strand are expanded apart from each other in parallel by the left-hand web strand wrapping around the left-hand deflecting means and by the right-hand web strand wrapping around the right-hand deflecting means. Expanding toward each other, i.e., a parallel offset in relation to one another, is alternatively conceivable, in principle. If the deflecting means have a corresponding pivotability, expanding apart from and toward each other would be possible as well. The web strands are offset in parallel in relation to their position before wrapping around the associated first deflecting means. The distance between the expanded web strands at right angles to the direction of web delivery will hereinafter be called the amount of expansion. To adjust the amount of expansion, at least one of the left-hand deflecting means is mounted movably in the frame by a path of adjustment in relation to the other left-hand deflecting means, and at least one of the right-hand deflecting means is mounted movably by a path of adjustment in the frame in relation to the other right-hand deflecting means. These at least two adjustment paths are preferably parallel to each other and, furthermore, preferably also equal. The parallelism of the offset can be guaranteed most simply by the left-hand deflecting means having the same cross-sectional shape among each other over their lengths acting on the left-hand web strand and also the right-hand deflecting means having the same cross-sectional shape and size among each other over their lengths acting on the right-hand web strand and, furthermore, by the deflection axes of the left-hand deflecting means and also the deflection axes of the right-hand deflecting means being parallel to each other in pairs in the adjusted positions.
According to the present invention, the first deflecting means or preferably the second deflecting means are movable relative to each other. In principle, both the first deflecting means can also be moved in relation to one another and the second deflecting means can also be moved in relation to one another. The movable deflecting means are preferably mounted such that the movable deflecting means can be moved along their path of adjustment independently from each other of the deflecting means. Due to the adjustability according to the present invention, the path lengths traveled by the web strands between the deflecting means associated with them can be varied in relation to one another, i.e., the path traveled by the left-hand web strand between the first left-hand deflecting means and the second left-hand deflecting means may be optionally greater or smaller than the path length traveled by the right-hand web strand between the first right-hand deflecting means and the second right-hand deflecting means. The deflecting means may, of course, also be adjusted to positions in which the path lengths of the two web strands between the respective associated deflecting means are equal.
The parallel offsets of the two web strands can therefore be selected to be different. One of the web strands may also pass over the web expanding device without parallel offset, while the other is offset in parallel. As a special advantage, the present invention offers the possibility of setting the parallel offset of one of the web strands independently from the other of the web strands.
The web expanding device according to the present invention can therefore form the final control element of a web edge control for at least one of the web strands and preferably for both web strands.
As far as the adjustability is concerned, each of the deflecting means may be mounted in the frame, e.g., in an individually movable manner. It is also conceivable, e.g., that the first left-hand deflecting means and the second right-hand deflecting means are mounted movably and the other two deflecting means are clamped in a fixed position in the frame. A possible adjustability for the purpose of compensating manufacturing tolerances shall be left out of consideration for the time being as far as the term of the fixed clamping is concerned. What is understood under adjustability in the present invention is that the deflecting means in question is still movable even while such an optionally performed adjustment is maintained. Furthermore, the movability is preferably such that the deflecting means in question can be moved into the desired adjusted position after the intake of a new web. It can especially preferably also be moved during the running production along its path of adjustment. Correspondingly, the expanding device comprises in the especially preferred embodiment a control means, which has a drive means for driving the movable deflecting means and can be advantageously expanded into a control or regulating means. However, the present invention also pertains, in principle, to a web expanding device in which the movable deflecting means are moved manually into the desired adjusted positions and are fixed in these adjusted positions.
The flexibility may be increased even further if the deflecting means and the longitudinal cutting means are movable together at right angles to the direction of web delivery in a linearly guided manner. The deflecting means and the longitudinal cutting means are preferably mounted together in the frame, and the frame as a whole is movable in relation to the processing unit or the plurality of processing units at right angles to the direction of web delivery, guided along a straight line.
Finally, it shall also be noted that it is not absolutely necessary to process a web cut lengthwise in the expanding device during the running production, but it may also happen that the web is already taken in with the width of a strand, because it had been already wound on a roll in the width of a strand.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which a preferred embodiment of the invention is illustrated.